Lead contamination poses a serious threat to drinking water safety. Both U.S. Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) agree that Lead is harmful to health, especially for children. There is no known safe level of lead in a child’s blood. Taking action to reduce these exposures can improve outcomes.

Lead is much more likely to enter water from household plumbing, especially for homes with lead pipes, faucets, and fixtures. For this reason, lead is a potential concern for all homes whether you are on a public water supply or private wells. Laws have restricted the amount of lead allowed in new pipes, fixtures, and solder, but many homes contain older materials. Lead pipes are more likely to be found in older cities and homes built before 1986. For homes without lead pipes, the most common problem is with brass or chrome-plated brass faucets and plumbing with lead solder.

Water utilities typically perform quality testing of water supplies at the treatment plant, or the upstream end of a system. By the time water has been delivered to a residence, the distribution system may have added contamination to the water, as is typical with lead contamination. Utilities, especially those in older communities, often don’t know the exact details of their distribution systems including pipe material, pipe size, or even the location of pipe. Early systems were built without meticulous records, and construction in the field often deviates from plan. Excavation to find out what is in the field is prohibitively expensive and intrusive. Prioritizing where to spend municipal dollars is a common issue.

Water Corrosivity plays a key factor!

Corrosivity describes how aggressive water is at corroding pipes and fixtures. Corrosive water can cause lead and copper in pipes to leach into drinking water and can eventually cause leaks in plumbing. Surface water and groundwater, both sources of drinking water, can potentially be corrosive.

Water corrosivity is controlled primarily by the water acidity and calcium carbonate content. In general, acidic water that has a pH less than 7 is more corrosive than water that pH is higher than 7. Water that is low in calcium carbonate is more corrosive than water that is high in calcium carbonate.

Guidance from the Centers for Disease Control and Prevention suggests that blood lead concentrations over 5 micrograms per deciliter of blood (µg/dL) may indicate lead poisoning. 3.5 micrograms per deciliter (µg/dL) is used to identify children with blood lead levels that are higher than most children’s levels. Various studies have found that blood lead concentrations are positively and significantly related to the amount of lead in drinking water.

The U.S. EPA set the maximum allowable concentration of lead in public drinking water at 15 micrograms per liter (µg/L). Since lead serves no beneficial purpose in the human body, it is the best if drinking water contains no lead.

Different from public water system, private wells are not regulated. The management and protection of well water depends on well owners. Annual water testing needs to be a routine. The basic water testing includes bacteria, nitrate, lead and any contaminants of local concern.

Lead in drinking water presents a complex problem for both public and private water users. If you have any questions about lead in your drinking water, contact your local health department.